The present invention relates to the field of integrated circuits in general and more particularly to the operation of integrated circuits.
Integrated circuits, such as semiconductor memories, may need close timing control over a range of operational temperatures to function properly. Unfortunately, integrated circuits may not function properly when the temperatures to which the integrated circuits are exposed are beyond the range of operational temperatures. Moreover, a system that includes the integrated circuits subjected to such temperatures may not function properly.
It is known to include a temperature sensor in integrated circuits for detecting temperatures beyond the range of operational temperatures to which the integrated circuits are subjected. For example, a conventional temperature sensor may detect when the temperature to which an integrated circuit is exposed exceeds a predetermined threshold temperature (an outside temperature range condition). An indication may be provided to the system based on the outside temperature range condition, such as by switching an output of the integrated circuit from one logic state to another.
It is known to select the predetermined threshold temperature during the fabrication of the integrated circuit. Unfortunately, it may be difficult to change the threshold at which the conventional temperature sensor indicates a temperature out of range condition after the integrated circuit is fabricated. Therefore, a need exists for improved temperature sensors in integrated circuits.
It is, therefore, an object of the present invention to allow improvement in the operation of fabricated integrated circuits.
It is a further object of the present invention to allow improved indications of temperature states of fabricated integrated circuits.
These and other objects are provided by temperature condition indicators and methods that provide a temperature state of a fabricated integrated circuit based on a temperature of the fabricated integrated circuit relative to a variable threshold temperature, wherein the variable threshold temperature can be adjusted during the operation of the fabricated integrated circuit. According to the present invention, a means for determining a temperature state of the fabricated integrated circuit is based on a temperature of the fabricated integrated circuit relative to a variable threshold temperature. A means for indicating the temperature state of the fabricated integrated circuit relative to the variable threshold temperature is adjusted during operation of the fabricated integrated circuit. For example, the threshold temperature can correspond to a temperature out of range condition beyond which the fabricated integrated circuit may not operate. The threshold temperature can be adjusted after the integrated circuit is packaged, by MRS mode, test mode or an electrical fuse, etc.
These and other objects are provided by temperature condition indicators and methods that provide a temperature state of a fabricated integrated circuit based on a temperature of the fabricated integrated circuit relative to a variable threshold temperature, wherein the variable threshold temperature can be adjusted during the operation of the fabricated integrated circuit. According to the present invention, a means for determining a temperature state of the fabricated integrated circuit is based on a temperature of the fabricated integrated circuit relative to a variable threshold temperature. A means for indicating the temperature state of the fabricated integrated circuit relative to the variable threshold temperature is adjusted during operation of the fabricated integrated circuit. For example, the threshold temperature can correspond to a temperature out of range condition beyond which the fabricated integrated circuit may not operate. The threshold temperature can be adjusted after the integrated circuit is packaged, by a tetode or an electrical fuse, etc.
In another aspect of the present invention, the temperature condition indicator includes a first current source which sources a first current based on the temperature in the fabricated integrated circuit. A second current source sources a second current based on the temperature in the fabricated integrated circuit wherein the temperature condition indicator provides the temperature state of the fabricated integrated circuit based on the first and second currents.